Class 05 EVS - Food for Health

Activities

Activity 1: Exploring Mango Products

Aim/Objective: To identify various food items made from mangoes that can be stored for long durations.

Materials Required:

• Notebook
• Knowledge of traditional food items

Procedure:

1. Think of different ways mangoes are consumed in your family.
2. List the items that are prepared specifically to last for many months.

Observation:

• Items like Aam papad, pickles, mango jam, and dried mango slices (Amchur) can be kept for a long time.

Explanation:

• Raw fruits spoil quickly due to high water content and microbial activity. By converting them into pickles (using oil/salt) or jam (using sugar) or by drying them (removing moisture), we create an environment where spoilage-causing microbes cannot thrive.

Conclusion:

• Food processing and preservation allow us to enjoy seasonal fruits throughout the year.

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Activity 2: Sun-Drying Tomatoes

Aim/Objective: To observe the effect of dehydration on food preservation.

Materials Required:

• Fresh tomato
• Knife
• Tray
• Sunlight

Procedure:

1. Cut a fresh tomato into thin slices.
2. Place the slices on a tray.
3. Keep the tray in a sunny window or balcony for 2-3 days.
4. Observe the changes in the appearance and texture of the tomato slices.

Observation:

• The tomato slices shrink, lose their juiciness, become dark in colour, and turn leathery or brittle.

Explanation:

• The sun's heat causes the water in the tomato to evaporate. Microbes like bacteria and fungi need moisture to grow and spoil food. By removing water (dehydration), we stop the growth of these microbes, effectively preserving the tomato.

Conclusion:

• Drying is an effective traditional method of food preservation by removing moisture.

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Activity 3: Traditional Preservation Inquiry

Aim/Objective: To learn about traditional food preservation techniques used in families.

Materials Required:

• Notebook
• Interview with elders

Procedure:

1. Ask the elders in your family how they keep food from spoiling without using modern gadgets like refrigerators.
2. Record at least one specific practice (e.g., salting fish, adding spices, or boiling milk).

Observation:

• Families use various methods like adding extra salt, sugar, or oil, and smoking or drying food items.

Explanation:

• Traditional methods utilize natural preservatives. Salt and sugar draw out moisture from microbes (osmosis), while oil creates an airtight seal that prevents oxygen from reaching the food, thereby inhibiting the growth of aerobic bacteria.

Conclusion:

• Traditional preservation methods are scientifically sound and have been used for generations to reduce food waste.

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Activity 4: Selection of Fresh Produce

Aim/Objective: To learn how to identify and select fresh fruits and vegetables in a market.

Materials Required:

• Visit to a vegetable market
• Observation of elders

Procedure:

1. Accompany an elder to the vegetable market.
2. Carefully observe how they check the produce (e.g., pressing, smelling, checking for spots or holes).
3. List the signs of "good" vs. "bad" produce.

Observation:

• Fresh vegetables are usually firm, bright in colour, and free from bruises or insect holes. Seasonal produce looks and smells better than off-season items.

Explanation:

• Selecting fresh produce ensures maximum nutritional value and better taste. Bruises or holes are entry points for microbes and pests, which speed up spoilage. Seasonal fruits are more likely to be naturally ripened and fresh as they don't require long-distance transport.

Conclusion:

• Careful selection is the first step in ensuring food safety and health.

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Activity 5: Understanding Mechanical Digestion

Aim/Objective: To observe how teeth break down food and the role of saliva in digestion.

Materials Required:

• A piece of food (e.g., bread or apple)
• A mirror

Procedure:

1. Take a bite of the food item.
2. Pay close attention to which teeth you use to bite (front) and which ones you use to chew (back).
3. Chew the food thoroughly until it becomes a soft mush.
4. Observe if the food tastes sweeter as you chew longer.

Observation:

• Front teeth (incisors) are used for cutting, and back teeth (molars) are used for grinding. Saliva mixes with the food, making it soft and easier to swallow.

Explanation:

• Digestion begins in the mouth. Teeth perform "mechanical digestion" by breaking large pieces into smaller ones, increasing the surface area for enzymes. Saliva contains the enzyme amylase, which starts breaking down complex starches into simpler sugars, which is why food may taste sweeter after prolonged chewing.

Conclusion:

• Proper chewing is essential for efficient digestion and nutrient absorption.